There has been known a technology for mounting a camera configured to image the outside on a mobile body such as a vehicle, taking a picture of the surroundings including a road surface, and estimating a movement amount of the mobile body from a movement amount of a pattern on the road surface in the images taken at two different clock times (see, “Development of a Monocular Ranging and Verification System Using an Onboard Camera”, SEI Technical Review, Issue No. 169, pp. 82 to 87, July 2006, for example). In such a technology, a movement amount may not be estimated with high accuracy due to an influence such as a shade of the own vehicle, for example, when a lane boundary position or a solid object is detected from the images taken, and the like. Thus, there has also been known a technology for improving detection accuracy of a lane boundary position or a solid object (see, Japanese Laid-open Patent Publication Nos. 2003-337999, 2009-265783, 2010-15367, 2004-338637, and 09-72716, for example).